At the center of the Milky Way, a mysterious gamma-ray glow has puzzled scientists since NASA’s Fermi Telescope detected it in 2008.

While some astronomers attribute the glow to pulsars—spinning remnants of exploded stars—others suggest it may come from collisions of dark matter, an invisible substance five times more abundant than regular matter.

New supercomputer simulations show that dark matter could produce the bulge-shaped glow, previously thought to favor the pulsar theory, CNN has reported.

This finding keeps both explanations viable and raises the possibility that evidence of dark matter could finally be observed.